Ice stores are used in refrigeration to cover an increased additional cooling requirement (peak load). The ice stores are usually charged over night when general energy requirements and energy costs are low.
  To charge and discharge the ice store a circuit with glycol-water mixture is used between the ice store and the compression refrigeration system. When charging the ice store the glycol-water mixture is cooled via a compression refrigeration system to below 0°C and thereby withdraws energy from the water in the ice store, causing the water to freeze. During discharging the melting ice withdraws energy from the glycol-water mixture causing the mixture to cool down. During this cooling process the ice store replaces the compression refrigeration system.
  ET 420 also includes a tank for the glycol-water mixture and a dry and wet cooling tower. The glycol-water tank is used as a collection point of the different energy flows: during the evaporation of the refrigerant in the compression refrigeration circuit and during discharging of the ice store, energy is withdrawn from the mixture, whereas during the condensing of the refrigerant energy is added. As required the cooling towers add energy to or withdraw energy from the mixture.
  The record of all required variables enables an energy balance for the individual processes.

  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

- Design and operation of an energy-efficient

  refrigeration system
- Function and operation of an ice store
  * charge
  * discharge
- Energy flow balance
- Energy transport via different media
- Compression refrigeration cycle in the log p-h

  diagram
- Function and operation of a wet cooling tower
- Function and operation of a dry cooling tower